Disclosed is a composition which comprises or consists essentially of a high melt index ethylene acid copolymer comprising monomer units derived from ethylene, an alkyl (meth)acrylate, a (meth)acrylic acid, and an optional comonomer. Also disclosed is a composition comprising the ethylene acid copolymer crosslinked with a polyamine, a polyvalent metal salt, or combinations thereof. Also disclosed is a solution of the ethylene acid copolymer which can be used for solutions application to substrates.